Refer to figure.
Profile Drag or Rotor Profile Drag is the drag created when the rotor is moved through the air, even when no lift is being generated and it is made up of the blades' form (pressure) and skin friction drag.

Rotor profile drag would at first seem to be independent of forward speed, as the increased drag on the advancing blade would be offset by the reduced drag of the retreating blade. In fact, this effect is proportional not to the blade speed, but to the square of the blade speed.

Although, it is almost constant at very low airspeeds, rotor profile drag rises gently as airspeed increases.